Specifications include, but are not limited to: • Record for up to 15 months duration. • Include split-beam transducers which transmit and receive at the three center frequencies of 38, 120 and 200 kHz, • Have a lightweight, small form factor for the acquisition/battery/transceiver electronics portion of the system (excluding transducers, all other components should be contained in a tube on the order of a meter in length and less than 20 cm in width and the weigh less than 30 kg in air, 15 kg in water), such that the electronics portion of the system comprises a complete remotely deployable package (i.e., needs to be easily mountable on a lightweight mooring). • The complete system and transducers should be rated for use in up to 1500 m water depth. • Capability for transmitting frequency modulated pulses (chirps) required. • Capability for recording four independent channels with the capability for multiplexing on each channel. ; • Inclusion of software for mission planning (allowing for duty-cycling of transmissions), software for calibration, as well as software to replay acquired data.